Corrigendum: γ′ Fibrinogen as a Predictor of Survival in Amyotrophic Lateral Sclerosis - Pronto-Laborinho, Ana Catarina; Lopes, Catarina S.; Conceição, Vasco A.; Gromicho, Marta; Santos, Nuno C.; de Carvalho, Mamede; Carvalho, Filomena A. (Frontiers in Cardiovascular Medicine, 2021)